By determining charging current I.sub.char and then subsequently utilising that determination of charging current I.sub.char in relation to battery current I.sub.bat and load current I.sub.load as a result of operation of a phone or other electronic device it is possible periodically to adjust the necessary charging current in order to operate the device in terms of recharging the battery to a target charging voltage, as well as providing adequate electrical current for operation of the associated phone or other electronic device.